JP2021071208A - Refrigerating device - Google Patents

Abstract

To return refrigerator oil to a compressor in a short time.SOLUTION: A refrigerating device comprises: a first compressor (40); a second compressor (50); a first gas-liquid separator (11); a second gas-liquid separator (21); a first suction pipe (16) connecting the first compressor (40) and the first gas-liquid separator (11), and opened on an upper side in the first gas-liquid separator (11); a second suction pipe (26) connecting the second compressor (50) and the second gas-liquid separator (21), and opened on an upper side in the second gas-liquid separator (21); a first pipe (17) connecting the first compressor (40) and the first gas-liquid separator (11), and opened on a bottom side in the first gas-liquid separator (11); a second pipe (27) connecting the second compressor (50) and the second gas-liquid separator (21), and opened on a bottom side in the second gas-liquid separator (21); a first opening/closing valve (18) provided in the first pipe (17); and a second opening/closing valve (28) provided in the second pipe (27).SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a refrigeration system.

As a conventional refrigerating apparatus, a first compressor which is a rotary compressor connected in parallel and a second compressor which is a scroll compressor are provided, and an accumulator is provided on the suction side of the first compressor. Yes (see Patent Document 1). In such a refrigerating apparatus, in order to return the refrigerating machine oil in the accumulator to the first compressor, a small-diameter oil return hole communicating with the inside of the accumulator is provided in the suction pipe connected to the first compressor and the accumulator. Sometimes.

Japanese Unexamined Patent Publication No. 2010-139155

In the above-mentioned conventional refrigerating apparatus, the second compressor, which is a scroll compressor, has a large amount of refrigerating machine oil discharged from the first compressor, which is a rotary compressor, and the refrigerating machine oil discharged from the second compressor is first compressed. It may return to the aircraft side. In this case, since the refrigerating machine oil is stored in the accumulator, it is difficult to supply the refrigerating machine oil to the second compressor, and the second compressor may run out of oil. In order to prevent the oil from running out in the second compressor, an oil return operation different from the air conditioning operation may be performed to return the refrigerating machine oil in the accumulator from the first compressor to the second compressor. In this case, the refrigerating machine oil in the accumulator is returned to the first compressor little by little from the oil return hole having a small diameter, so it takes time to return the refrigerating machine oil to the second compressor. As a result, it is necessary to perform the oil return operation for a long time in order to return the refrigerating machine oil to the first compressor. In particular, when the refrigerating device is used in an air conditioner, there is a problem that the user's comfort is lowered because the normal air conditioning operation is not performed for a long time in order to return the refrigerating machine oil to the first compressor.

The present disclosure proposes a refrigerating apparatus capable of reducing the time required to return the refrigerating machine oil to the compressor.

The refrigerating device of the present disclosure is
A first compressor having a first compression mechanism unit and
A second compressor having a second compression mechanism,
A first gas-liquid separator provided on the suction side of the first compressor and separating a refrigerant containing refrigerating machine oil into a gas containing a gas refrigerant and a liquid containing a liquid refrigerant and refrigerating machine oil.
A second gas-liquid separator provided on the suction side of the second compressor and separating the refrigerant containing the refrigerating machine oil into a gas containing a gas refrigerant and a liquid containing a liquid refrigerant and the refrigerating machine oil.
A first suction pipe having an opening at one end on the upper side in the first gas-liquid separator and connecting the first compressor and the first gas-liquid separator.
A second suction pipe having an opening at one end on the upper side in the second gas-liquid separator and connecting the second compressor and the second gas-liquid separator, and the second suction pipe.
One end is opened on the bottom side in the first gas-liquid separator, and the first pipe for connecting the first compressor and the first gas-liquid separator, and the first pipe.
A second pipe for connecting the second compressor and the second gas-liquid separator with an opening at one end on the bottom side of the second gas-liquid separator, and
The first on-off valve provided in the first pipe and
It is characterized by being provided with a second on-off valve provided in the second pipe.

According to the present disclosure, by opening the first on-off valve, the liquid containing the refrigerating machine oil and the liquid refrigerant stored in the bottom of the first gas-liquid separator is returned to the first compressor via the first pipe. Is done. As a result, the refrigerating machine oil can be returned to the first compressor in a short time as compared with the case where the refrigerating machine oil is returned to the first compressor from only the first suction pipe. Similarly, by opening the second on-off valve, the liquid containing the refrigerating machine oil and the liquid refrigerant stored in the bottom portion of the second gas-liquid separator is returned to the second compressor via the second pipe. As a result, the refrigerating machine oil can be returned to the second compressor in a short time as compared with the case where the refrigerating machine oil is returned to the second compressor from only the second suction pipe. As a result, the oil return operation for returning the refrigerating machine oil to the first compressor and the second compressor is shortened, so that the user's comfort can be improved.

The refrigerating apparatus of one embodiment does not include an oil leveling pipe between the first compressor and the second compressor.

In an air conditioner in which the first compressor and the second compressor are provided in separate outdoor units, when an oil leveling pipe is provided between the first compressor and the second compressor, the degree of freedom in installing the outdoor unit is remarkable. descend. According to the above embodiment, since the oil leveling pipe is not provided between the first compressor and the second compressor, the degree of freedom in installing the refrigerating device can be improved.

In the refrigerating apparatus of one embodiment, the first compression mechanism portion of the first compressor and the first gas-liquid separator are connected by the first pipe, and the second compression mechanism of the second compressor is connected. The unit and the second gas-liquid separator are connected by the second pipe.

In the refrigeration apparatus of one embodiment,
The first compression mechanism unit
With the lower cylinder,
It is equipped with an upper cylinder located above the lower cylinder.
The second compression mechanism unit
With the lower cylinder,
It is equipped with an upper cylinder located above the lower cylinder.
The first pipe is connected to the upper cylinder of the first compression mechanism unit, and is connected to the upper cylinder.
The first suction pipe is connected to the lower cylinder of the first compression mechanism unit.
The second pipe is connected to the upper cylinder of the second compression mechanism unit, and is connected to the upper cylinder.
The second suction pipe is connected to the lower cylinder of the second compression mechanism section.

According to the above embodiment, since the first pipe is connected to the upper cylinder, when the first on-off valve is opened, the liquid containing the refrigerating machine oil flows from the first gas-liquid separator through the first pipe to the first pipe. It is supplied to the first compression mechanism section of the compressor. As a result, the structure of the refrigerating device can be simplified. Similarly, since the second pipe is connected to the upper cylinder, when the second on-off valve is opened, the liquid containing the refrigerating machine oil flows from the second gas-liquid separator through the second pipe to the second compressor. 2 It is supplied to the compression mechanism section. As a result, the structure of the refrigerating device can be simplified.

In the refrigeration apparatus of one embodiment,
The first compression mechanism unit
With the lower cylinder,
It is equipped with an upper cylinder located above the lower cylinder.
The second compression mechanism unit
With the lower cylinder,
It is equipped with an upper cylinder located above the lower cylinder.
The first suction pipe is
A lower suction pipe connecting the first gas-liquid separator and the lower cylinder of the first compression mechanism unit, and
It has an upper suction pipe that connects the first gas-liquid separator and the upper cylinder of the first compression mechanism unit.
The second suction pipe is
A lower suction pipe connecting the second gas-liquid separator and the lower cylinder of the second compression mechanism unit, and
It has an upper suction pipe that connects the second gas-liquid separator and the upper cylinder of the second compression mechanism unit.
The first pipe is connected to the upper suction pipe of the first suction pipe.
The second pipe is connected to the upper suction pipe of the second suction pipe.

According to the above embodiment, since the first pipe is connected to the upper suction pipe connected to the upper cylinder, when the first on-off valve is opened, the liquid containing the refrigerating machine oil returned to the first compression mechanism unit is opened. Is supplied from the first gas-liquid separator through the upper suction pipe to the first compression mechanism portion of the first compressor. As a result, the structure of the refrigerating device can be simplified. Similarly, since the second pipe is connected to the upper suction pipe connected to the upper cylinder, when the second on-off valve is opened, the liquid containing the refrigerating machine oil returned to the second compression mechanism is second. It is supplied from the gas-liquid separator through the upper suction pipe to the second compression mechanism of the second compressor. As a result, the structure of the refrigerating device can be simplified.

In the refrigeration apparatus of one embodiment,
The refrigerant circuit includes a heat source side heat exchanger, an expansion mechanism, and a user side heat exchanger.
The heat source side fan that supplies air to the heat source side heat exchanger and
The user side fan that supplies air to the user side heat exchanger and
The refrigerant circuit, the heat source side fan, and the user side fan so that the oil return operation for returning the refrigerating machine oil dispersed in the refrigerant circuit to the first gas-liquid separator and the second gas-liquid separator can be executed. Further equipped with a control unit to control
After executing the oil return operation, the control unit stops the first compressor and the second compressor, and opens the first on-off valve and the second on-off valve.

According to the above embodiment, the first on-off valve and the second on-off valve are opened after the oil return operation of returning the refrigerating machine oil dispersed in the refrigerant circuit to the first gas-liquid separator and the second gas-liquid separator is executed. As a result, the first on-off valve is opened in a state where the refrigerating machine oil dispersed in the refrigerant circuit is collected in the first gas-liquid separator, so that the refrigerating machine oil can be returned from the first gas-liquid separator to the first compressor. The required time is shortened, and the refrigerating machine oil can be efficiently returned to the first compressor. Similarly, since the second on-off valve is opened in the state where the refrigerating machine oil dispersed in the refrigerant circuit is collected in the second gas-liquid separator, in order to return the refrigerating machine oil from the second gas-liquid separator to the second compressor. The required time is shortened and the refrigerating machine oil can be efficiently returned to the second compressor.

It is a block diagram of the air conditioner which concerns on 1st Embodiment of this disclosure. It is a schematic cross-sectional view of the 1st compressor which concerns on 1st Embodiment. It is a block diagram of the air conditioner which concerns on 1st Embodiment. It is a block diagram of the air conditioner which concerns on 2nd Embodiment of this disclosure. It is a schematic cross-sectional view of the 1st compressor which concerns on 2nd Embodiment. It is a block diagram of the air conditioner which concerns on 3rd Embodiment of this disclosure. It is a schematic cross-sectional view of the 1st compressor which concerns on 3rd Embodiment.

Hereinafter, the air conditioner 1 according to the embodiment of the present disclosure will be described with reference to the accompanying drawings.

[First Embodiment]
FIG. 1 is a configuration diagram of an air conditioner 1 according to the first embodiment of the present disclosure. The air conditioner 1 of the present embodiment is an example of the refrigerating apparatus according to the present disclosure.

(overall structure)
Referring to FIG. 1, the air conditioner 1 according to the present embodiment is a first indoor unit connected to a first outdoor unit 10, a second outdoor unit 20, a first outdoor unit 10, and a second outdoor unit 20. A 30A and a second indoor unit 30B are provided. The first outdoor unit 10 and the second outdoor unit 20 and the first indoor unit 30A and the second indoor unit 30B are connected by connecting pipes L1 and L2. As a result, a refrigerant circuit RC for circulating the refrigerant is configured between the first outdoor unit 10 and the second outdoor unit 20 and the first indoor unit 30A and the second indoor unit 30B.

The first outdoor unit 10 is connected to the connecting pipe L1 via the closing valve 2A, and is connected to the connecting pipe L2 via the closing valve 3A. Similarly, the second outdoor unit 20 is connected to the connecting pipe L1 via the closing valve 2B, and is connected to the connecting pipe L2 via the closing valve 3B. As a result, in the refrigerant circuit RC, the first outdoor unit 10 and the second outdoor unit 20 are connected in parallel.

(1st outdoor unit)
The first outdoor unit 10 includes a first compressor 40, a first gas-liquid separator 11, a first outdoor heat exchanger 12, a first outdoor fan 13, a first outdoor expansion valve 14, and a first fourteenth outdoor unit. A road switching valve 15 is provided.

The first compressor 40 of this embodiment is a rotary compressor. The first compressor 40 contains a first compression mechanism unit 41 and a first motor 42 that drives the first compression mechanism unit 41. When the first compression mechanism unit 41 is driven by the first motor 42, the first compressor 40 sucks the refrigerant from the first suction pipe 16 connected to the suction side of the first compressor 40 and compresses it. It is discharged to the refrigerant pipe on the discharge side of the first compressor 40. Further, the first compressor 40 is configured so that the operating frequency can be changed according to the control of the control unit 60 (shown in FIG. 3).

The first gas-liquid separator 11 is provided on the suction side of the first compressor 40. The first gas-liquid separator 11 separates the refrigerant containing the refrigerating machine oil that has flowed into the first gas-liquid separator 11 into a gas containing a gas refrigerant and a liquid containing a liquid refrigerant and the refrigerating machine oil. At the bottom of the first gas-liquid separator 11, a first liquid pool portion 11a is formed by the liquid separated from the refrigerant.

The first compressor 40 and the first gas-liquid separator 11 are connected by a first suction pipe 16. The first suction pipe 16 is provided to supply the gas containing the gas refrigerant separated from the refrigerant by the first gas-liquid separator 11 to the first compressor 40.

Further, the first compression mechanism portion 41 of the first compressor 40 and the first gas-liquid separator 11 are connected by a first pipe 17. The first pipe 17 is a pipe for connecting the first compressor 40 and the first gas-liquid separator 11. The first pipe 17 is provided to return the liquid containing the refrigerating machine oil and the liquid refrigerant separated from the refrigerant by the first gas-liquid separator 11 to the first compressor 40. Further, the first pipe 17 is provided with a first on-off valve 18 that allows or blocks the flow of liquid in the first pipe 17. The first on-off valve 18 is configured so that the opening and closing can be changed according to the control of the control unit 60 (shown in FIG. 3).

The first outdoor heat exchanger 12 is a heat exchanger that exchanges heat between the refrigerant flowing through the refrigerant circuit RC and the outdoor air. The first outdoor heat exchanger 12 functions as a condenser during the cooling operation and as an evaporator during the heating operation. The first outdoor heat exchanger 12 is an example of the heat source side heat exchanger according to the present disclosure.

The first outdoor fan 13 is provided so as to supply outdoor air to the first outdoor heat exchanger 12. The first outdoor fan 13 of the present embodiment is configured so that the rotation speed can be changed according to the control of the control unit 60 (shown in FIG. 3). The first outdoor fan 13 according to the present embodiment is an example of the heat source side fan according to the present disclosure.

The first outdoor expansion valve 14 decompresses the refrigerant and adjusts the flow rate of the refrigerant. The first outdoor expansion valve 14 is provided in a refrigerant pipe connecting the first outdoor heat exchanger 12 and the closing valve 3A. The first outdoor expansion valve 14 adjusts the flow rate of the refrigerant flowing through the first indoor unit 30A or the second indoor unit 30B by adjusting the opening degree of the first outdoor expansion valve 14 in the heating operation and the cooling operation. .. Further, the first outdoor expansion valve 14 is configured so that the opening degree can be adjusted by the control of the control unit 60 (shown in FIG. 2). The first outdoor expansion valve 14 is an example of the expansion mechanism according to the present disclosure.

The first four-way switching valve 15 connects the discharge side of the first compressor 40 and the first outdoor heat exchanger 12 during the cooling operation, and also connects the suction side of the first compressor 40 with the first indoor unit 30A and the first indoor unit 30A. Connect to the second indoor unit 30B (switching position of solid line in the figure). Also. The first four-way switching valve 15 connects the discharge side of the first compressor 40 to the first indoor unit 30A and the second indoor unit 30B during the heating operation, and connects the suction side of the first compressor 40 to the first. It is connected to the outdoor heat exchanger 12 (switching position shown by the broken line in the figure). The first four-way switching valve 15 is configured so that the switching position of the solid line in the figure and the switching position of the broken line in the figure can be switched by the control of the control unit 60 (shown in FIG. 3).

In the first outdoor unit 10, the first compressor 40, the first gas-liquid separator 11, the first outdoor heat exchanger 12, the first outdoor expansion valve 14, the first four-way switching valve 15, and the first 1 The on-off valve 18 and the refrigerant pipe connecting them form a part of the refrigerant circuit RC. Further, the refrigerant pipe includes a first suction pipe 16 and a first pipe 17.

(2nd outdoor unit)
The second outdoor unit 20 includes a second compressor 50, a second gas-liquid separator 21, a second outdoor heat exchanger 22, a second outdoor fan 23, a second outdoor expansion valve 24, and a second fourth. A road switching valve 25 is provided. The configuration of the second outdoor unit 20 is the same as the configuration of the first outdoor unit 10.

The second compressor 50 of this embodiment is a rotary compressor. The second compressor 50 contains a second compression mechanism section 51 and a second motor 52 that drives the second compression mechanism section 51. When the second compression mechanism section 51 is driven by the second motor 52, the second compressor 50 sucks the refrigerant from the second suction pipe 26 connected to the suction side of the second compressor 50 and compresses it. It is discharged to the refrigerant pipe on the discharge side of the second compressor 50. Further, the second compressor 50 is configured so that the operating frequency can be changed according to the control of the control unit 60 (shown in FIG. 3).

The second gas-liquid separator 21 is provided on the suction side of the second compressor 50. The second gas-liquid separator 21 separates the refrigerant containing the refrigerating machine oil that has flowed into the second gas-liquid separator 21 into a gas containing a gas refrigerant and a liquid containing a liquid refrigerant and the refrigerating machine oil. At the bottom of the second gas-liquid separator 21, a second liquid reservoir 21a is formed by the liquid separated from the refrigerant.

The second compressor 50 and the second gas-liquid separator 21 are connected by a second suction pipe 26. The second suction pipe 26 is provided to supply the gas containing the gas refrigerant separated from the refrigerant by the second gas-liquid separator 21 to the second compressor 50.

Further, the second compression mechanism portion 51 of the second compressor 50 and the second gas-liquid separator 21 are connected by a second pipe 27. The second pipe 27 is a pipe for connecting the second compressor 50 and the second gas-liquid separator 21. The second pipe 27 is provided to return the liquid containing the refrigerating machine oil and the liquid refrigerant separated from the refrigerant by the second gas-liquid separator 21 to the second compressor 50. Further, the second pipe 27 is provided with a second on-off valve 28 that allows or blocks the flow of liquid in the second pipe 27. The second on-off valve 28 is configured so that the opening and closing can be changed according to the control of the control unit 60 (shown in FIG. 3).

The second outdoor heat exchanger 22 is a heat exchanger that exchanges heat between the refrigerant flowing through the refrigerant circuit RC and the outdoor air. The second outdoor heat exchanger 22 functions as a condenser during the cooling operation and as an evaporator during the heating operation. The second outdoor heat exchanger 22 is an example of the heat source side heat exchanger according to the present disclosure.

The second outdoor fan 23 is provided so as to supply outdoor air to the second outdoor heat exchanger 22. The second outdoor fan 23 of the present embodiment is configured so that the rotation speed can be changed according to the control of the control unit 60 (shown in FIG. 3). The second outdoor fan 23 according to the present embodiment is an example of the heat source side fan according to the present disclosure.

The second outdoor expansion valve 24 decompresses the refrigerant and adjusts the flow rate of the refrigerant. The second outdoor expansion valve 24 is provided in the refrigerant pipe connecting the second outdoor heat exchanger 22 and the closing valve 3B. The second outdoor expansion valve 24 adjusts the flow rate of the refrigerant flowing through the first indoor unit 30A or the second indoor unit 30B by adjusting the opening degree of the second outdoor expansion valve 24 in the heating operation and the cooling operation. .. Further, the second outdoor expansion valve 24 is configured so that the opening degree can be adjusted by the control of the control unit 60 (shown in FIG. 3). The second outdoor expansion valve 24 is an example of the expansion mechanism according to the present disclosure.

The second four-way switching valve 25 connects the discharge side of the second compressor 50 and the second outdoor heat exchanger 22 during the cooling operation, and also connects the suction side of the second compressor 50 with the first indoor unit 30A and the first indoor unit 30A. Connect to the second indoor unit 30B (switching position of solid line in the figure). Also. The second four-way switching valve 25 connects the discharge side of the second compressor 50 to the first indoor unit 30A and the second indoor unit 30B during the heating operation, and connects the suction side of the second compressor 50 to the second. It is connected to the outdoor heat exchanger 22 (switching position shown by the broken line in the figure). The second four-way switching valve 25 is configured so that the switching position of the solid line in the figure and the switching position of the broken line in the figure can be switched by the control of the control unit 60 (shown in FIG. 3).

In the second outdoor unit 20, the second compressor 50, the second gas-liquid separator 21, the second outdoor heat exchanger 22, the second outdoor expansion valve 24, the second four-way switching valve 25, and the second The two on-off valves 28 and the refrigerant pipes connecting them form a part of the refrigerant circuit RC. Further, the refrigerant pipe includes a second suction pipe 26 and a second pipe 27.

(Indoor unit)
The first indoor unit 30A includes a first indoor heat exchanger 31A, a first indoor fan 32A that supplies indoor air to the first indoor heat exchanger 31A, and a first indoor expansion valve 33A.

The first indoor heat exchanger 31A is a heat exchanger that exchanges heat between the refrigerant flowing through the refrigerant circuit and the indoor air. The first chamber heat exchanger 31A functions as an evaporator during the cooling operation and as a condenser during the heating operation. The first indoor heat exchanger 31A is an example of the user-side heat exchanger according to the present disclosure.

The first indoor fan 32A is configured so that the rotation speed can be changed by the control of the control unit 60 (shown in FIG. 3). The first indoor fan 32A according to the present embodiment is an example of a user-side fan according to the present disclosure.

The first chamber expansion valve 33A adjusts the flow rate of the refrigerant flowing through the first chamber heat exchanger 31A by adjusting the opening degree of the first chamber expansion valve 33A.

The second indoor unit 30B includes a second indoor heat exchanger 31B, a second indoor fan 32B that supplies indoor air to the second indoor heat exchanger 31B, and a second indoor expansion valve 33B.

The second indoor heat exchanger 31B is a heat exchanger that exchanges heat between the refrigerant flowing through the refrigerant circuit and the indoor air. The second chamber heat exchanger 31B functions as an evaporator during the cooling operation and as a condenser during the heating operation. The second indoor heat exchanger 31B is an example of the user-side heat exchanger according to the present disclosure.

The second indoor fan 32B is configured so that the rotation speed can be changed by the control of the control unit 60 (shown in FIG. 3). The second indoor fan 32B according to the present embodiment is an example of a user-side fan according to the present disclosure.

The second chamber expansion valve 33B adjusts the flow rate of the refrigerant flowing through the second chamber heat exchanger 31B by adjusting the opening degree of the second chamber expansion valve 33B.

The refrigerant circuit RC of the air conditioner 1 of the present embodiment connects the first outdoor unit 10, the second outdoor unit 20, the first indoor unit 30A, the second indoor unit 30B, and their components. It consists of a refrigerant pipe. Specifically, the refrigerant circuit RC of the air conditioner 1 of the present embodiment includes the first compressor 40, the first gas-liquid separator 11, the first outdoor heat exchanger 12, and the first outdoor expansion valve 14. The first four-way switching valve 15, the second compressor 50, the second gas-liquid separator 21, the second outdoor heat exchanger 22, the second outdoor expansion valve 24, and the second four-way switching valve. 25, a first chamber heat exchanger 31A, a second chamber heat exchanger 31B, a first chamber expansion valve 33A, a second chamber expansion valve 33B, and a refrigerant pipe connecting them. Further, the refrigerant pipes include connecting pipes L1 and L2, a first suction pipe 16, a second suction pipe 26, a first pipe 17, and a second pipe 27. The first compressor 40 and the second compressor 50 are the first outdoor heat exchanger 12, the second outdoor heat exchanger 22, the first outdoor expansion valve 14, the second outdoor expansion valve 24, and the first indoor heat exchange. It is included in the refrigerant circuit RC together with the vessel 31A, the second chamber heat exchanger 31B, the first chamber expansion valve 33A, and the second chamber expansion valve 33B.

Further, as shown in FIG. 1, the air conditioner 1 according to the present disclosure does not include an oil leveling pipe for connecting the first compressor 40 and the second compressor 50.

(Detailed structure around the compressor)
Hereinafter, the detailed structure of the first compressor 40 and its surroundings will be described. Further, the second outdoor unit 20 of the present embodiment has the same configuration as the first outdoor unit 10, and a detailed description thereof will be omitted. Specifically, the second compressor 50 of the second outdoor unit 20, the second gas-liquid separator 21, the second suction pipe 26, the second pipe 27, and the second on-off valve 28 are the first outdoor unit 10. It has the same configuration as the first compressor 40, the first gas-liquid separator 11, the first suction pipe 16, the first pipe 17, and the first on-off valve 18.

FIG. 2 is a schematic vertical sectional view showing the periphery of the first compressor 40 according to the present embodiment.

Referring to FIG. 2, the first compressor 40 of the present embodiment includes a first compression mechanism unit 41, a first motor 42 for driving the first compression mechanism unit 41, a first compression mechanism unit 41, and a first motor. A closed container 43 for accommodating the 42 is provided. The first compressor 40 of the present embodiment is a high-pressure dome type rotary compressor.

The first compressor 40 according to the present embodiment is a compressor having a one-cylinder configuration. In the first compressor 40, the first compression mechanism portion 41 is arranged on the lower side of the closed container 43, and the first motor 42 is arranged on the upper side of the first compression mechanism portion 41. The first motor 42 has an annular stator 42a fixed inside the closed container 43 and a rotor 42b arranged inside the stator 42a. The rotation of the rotor 42b drives the first compression mechanism 41 via the shaft 42c fixed to the rotor 42b.

The first compression mechanism unit 41 sucks the gas refrigerant from the first gas-liquid separator 11 through the first suction pipe 16. The first compression mechanism unit 41 compresses the sucked gas refrigerant, and discharges the compressed high-temperature and high-pressure gas refrigerant (discharge gas) into the closed container 43. The discharged gas discharged from the first compression mechanism unit 41 is provided on the upper side of the first motor 42 after cooling the first motor 42 through the gap between the stator 42a and the rotor 42b of the first motor 42. It is discharged from the discharge pipe 43a to the outside of the closed container 43.

The first compression mechanism portion 41 includes a front head 41a attached to the inner surface of the closed container 43, a cylinder 41b attached to the lower side of the front head 41a, and a rear head 41c attached to the lower side of the cylinder 41b. .. The cylinder chamber 41d is formed by the front head 41a, the cylinder 41b, and the rear head 41c. Further, the first compression mechanism unit 41 includes a piston 41f composed of a roller and a vane that swing in the cylinder chamber 41d.

The first compression mechanism portion 41 of the present embodiment includes a suction passage 44 formed in the cylinder 41b. One end of the suction passage 44 is open to the outer surface of the cylinder 41b, and the other end of the suction passage 44 is open to the cylinder chamber 41d.

The first gas-liquid separator 11 has a substantially cylindrical shape and is installed so as to extend vertically. At the bottom of the first gas-liquid separator 11, a first liquid reservoir 11a in which a liquid containing a liquid refrigerant separated from the refrigerant and a liquid containing refrigerating machine oil is stored is formed.

The first suction pipe 16 connects the first compressor 40 and the first gas-liquid separator 11. One end of the first suction pipe 16 is open on the upper side in the first gas-liquid separator 11. The upper side in the first gas-liquid separator 11 is above the half position in the height direction of the first gas-liquid separator 11. In the state shown in FIG. 2, one end of the first suction pipe 16 is open above the first liquid pool portion 11a formed in the first gas-liquid separator 11. As a result, it is difficult for the liquid refrigerant stored in the first liquid pool portion 11a to be sucked into the first suction pipe 16, so that damage to the first compression mechanism portion 41 due to liquid compression in the first compressor 40 is suppressed. The other end of the first suction pipe 16 is connected to the first compression mechanism portion 41 of the first compressor 40. Specifically, the other end of the first suction pipe 16 is connected to a suction passage 44 formed in the cylinder of the first compression mechanism portion 41. As a result, the cylinder chamber 41d of the first compressor 40 communicates with the upper side in the first gas-liquid separator 11 via the first suction pipe 16 and the suction passage 44.

Further, the first suction pipe 16 extends in the vertical direction in the first gas-liquid separator 11 and has an oil return hole 16a opened below in the first gas-liquid separator 11. In the state shown in FIG. 2, the oil return hole 16a is open to the first liquid pool portion 11a formed in the first gas-liquid separator 11. As a result, the liquid containing the refrigerating machine oil accumulated in the bottom of the first gas-liquid separator 11 is returned from the oil return hole 16a to the cylinder chamber 41d of the first compressor 40 via the first suction pipe 16. The oil return hole 16a is a hole having a small diameter so that a large amount of liquid refrigerant does not return to the first compression mechanism section 41 during the operation of the first compressor 40.

The first pipe 17 of the present embodiment connects the first compressor 40 and the first gas-liquid separator 11. One end of the first pipe 17 is open on the bottom side in the first gas-liquid separator 11. The bottom side in the first gas-liquid separator 11 is below the half position in the height direction of the first gas-liquid separator 11. In the state shown in FIG. 2, one end of the first pipe 17 is opened by the first liquid pool portion 11a formed in the first gas-liquid separator 11. The other end of the first pipe 17 of the present embodiment is connected to the first suction pipe 16.

The first on-off valve 18 is provided in the first pipe 17. The first on-off valve 18 is configured so that opening and closing can be switched by the control of the control unit 60 (shown in FIG. 3).

Further, the opening of the first pipe 17 in the first gas-liquid separator 11 is opened below the opening of the first suction pipe 16 in the first gas-liquid separator 11 in the direction of gravity. In other words, the opening of the first suction pipe 16 in the first gas-liquid separator 11 is opened above the opening of the first pipe 17 in the first gas-liquid separator 11 in the direction of gravity.

FIG. 3 is a block diagram of the air conditioner 1 according to the present embodiment.

Referring to FIG. 3, the air conditioner 1 according to the present embodiment includes the components included in the refrigerant circuit RC (shown in FIG. 1), the first outdoor fan 13, the second outdoor fan 23, and the first indoor fan 32A. , And a control unit 60 connected to the second chamber fan 32B. The control unit 60 of the present embodiment includes the first compressor 40 of the first outdoor unit 10, the first on-off valve 18, the first outdoor fan 13, the first outdoor expansion valve 14, and the second outdoor unit 20. The second compressor 50, the second on-off valve 28, the second outdoor fan 23, the second outdoor expansion valve 24, the first indoor fan 32A, the second indoor fan 32B, and the first indoor expansion valve 33A. , Controls the second chamber expansion valve 33B. Specifically, the control unit 60 controls the operating frequencies of the first compressor 40 and the second compressor 50. Further, the control unit 60 controls the opening and closing of the first on-off valve 18 and the second on-off valve 28. The control unit 60 controls the rotation speeds of the first outdoor fan 13, the second outdoor fan 23, the first indoor fan 32A, and the second indoor fan 32B. Further, the control unit 60 controls the opening degree of the first outdoor expansion valve 14, the second outdoor expansion valve 24, the first indoor expansion valve 33A, and the second indoor expansion valve 33B.

(Operation of air conditioner)
The air conditioner 1 of the present embodiment can perform a cooling operation, a heating operation, and an oil return operation for recovering the refrigerating machine oil dispersed in the refrigerant circuit RC. Hereinafter, the operation of the air conditioner 1 in the oil return operation will be described with reference to FIG.

(Oil return operation)
After the oil return operation, the oil return operation of the present embodiment is performed in the cooling cycle. When the air conditioner 1 performs the oil return operation, the first four-way switching valve 15 and the second four-way switching valve are switched to the switching positions shown by the solid lines in FIG. Start operation. Then, the first outdoor expansion valve 14 and the second outdoor expansion valve 24 are opened to a predetermined opening degree. The high-temperature and high-pressure gas refrigerant discharged from the first compressor 40 is condensed by heat exchange with the outdoor air supplied by the first outdoor fan 13 in the first outdoor heat exchanger 12 to become a liquid refrigerant. Similarly, the high-temperature and high-pressure gas refrigerant discharged from the second compressor 50 is condensed by heat exchange with the outdoor air supplied by the second outdoor fan 23 in the second outdoor heat exchanger 22 to become a liquid refrigerant.

The operating frequency of the first compressor 40 in the oil return operation is higher than the operating frequency of the first compressor 40 in the cooling operation. Similarly, the operating frequency of the second compressor 50 in the oil return operation is higher than the operating frequency of the second compressor 50 in the cooling operation. Further, the opening degree of the first outdoor expansion valve 14 in the oil return operation is larger than the opening degree of the first outdoor expansion valve 14 in the cooling operation. Similarly, the opening degree of the second outdoor expansion valve 24 in the oil return operation is larger than the opening degree of the second outdoor expansion valve 24 in the cooling operation.

Next, the liquid refrigerant from the first outdoor heat exchanger 12 is decompressed by the first outdoor expansion valve 14, then passes through the first indoor heat exchanger 31A and the second indoor heat exchanger 31B, and is passed through the first air-liquid. Return to the separator 11 or the second gas-liquid separator 21. Similarly, the liquid refrigerant from the second outdoor heat exchanger 22 passes through the first indoor heat exchanger 31A and the second indoor heat exchanger 31B after being decompressed by the second outdoor expansion valve 24, and is passed through the first air-liquid. Return to the separator 11 or the second gas-liquid separator 21. At this time, the first chamber fan 32A and the second chamber fan 32B are controlled by the control unit 60 so as not to operate.

In the oil return operation, the air conditioner 1 operates in this way, so that the liquid refrigerant separates the first air-liquid separator 11 and the second air-liquid from the first outdoor heat exchanger 12 and the second outdoor heat exchanger 22. It circulates in the vessel 21. The refrigerating machine oil dispersed in the refrigerant circuit RC is dissolved in the liquid refrigerant circulating in the refrigerant circuit RC and recovered in the first gas-liquid separator 11 and the second gas-liquid separator 21.

In the oil return operation, both the first on-off valve 18 and the second on-off valve 28 are closed. In the present embodiment, after the oil return operation, the control unit 60 controls the first on-off valve 18 and the second on-off valve so that the first on-off valve 18 allows the flow of the fluid in the first pipe 17. The second on-off valve 28 is controlled so that the 28 allows the flow of fluid in the second pipe 27. By opening the first on-off valve 18 and the second on-off valve 28 after the oil return operation, the liquid containing the refrigerating machine oil stored in the first gas-liquid separator 11 and the second gas-liquid separator 21 is released into the first compressor. It is returned to 40 and the second compressor 50.

After the oil return operation (generally executed in the cooling cycle), by opening the first on-off valve 18 provided in the first pipe 17, the refrigerating machine oil stored in the bottom of the first gas-liquid separator 11 and The liquid containing the liquid refrigerant is returned to the first compressor 40 via the first pipe 17. As a result, the refrigerating machine oil can be returned to the first compressor 40 in a short time as compared with the case where the refrigerating machine oil is returned to the first compressor 40 from only the first suction pipe 16. Similarly, by opening the second on-off valve 28 provided in the second pipe 27, the liquid containing the refrigerating machine oil and the liquid refrigerant stored in the bottom of the second gas-liquid separator 21 can make the second pipe 27. It is returned to the second compressor 50 via. As a result, the refrigerating machine oil can be returned to the second compressor 50 in a short time as compared with the case where the refrigerating machine oil is returned to the second compressor 50 from only the second suction pipe 26. As a result, the time during which the air conditioning operation is stopped in order to return the refrigerating machine oil to the first compressor 40 and the second compressor 50 is shortened, so that the user's comfort can be improved.

When the air conditioner is provided with the first compressor and the second compressor in separate outdoor units, and the oil leveling pipe is provided between the first compressor and the second compressor, the oil leveling pipe can be routed. The degree of freedom in installing the outdoor unit is reduced. On the other hand, according to the above embodiment, since the oil leveling pipe is not provided between the first compressor 40 and the second compressor 50, the first compressor 40 and the second compressor 50 can be freely installed. The decrease in degree can be suppressed. In particular, when the first compressor 40 and the second compressor 50 are provided in the separate first outdoor unit 10 and the second outdoor unit 20, as in the present embodiment, the first outdoor unit is provided. The degree of freedom in installing the machine 10 and the second outdoor unit 20 can be improved.

According to the above embodiment, after executing the oil return operation of returning the refrigerating machine oil dispersed in the refrigerant circuit RC to the first gas-liquid separator 11 and the second gas-liquid separator 21, the first on-off valve 18 and the second on-off valve 18 and the second on-off Open valve 28. That is, since the first on-off valve 18 is opened in a state where the refrigerating machine oil dispersed in the refrigerant circuit RC is collected by the first gas-liquid separator 11, the refrigerating machine oil is transferred from the first gas-liquid separator 11 to the first compressor 40. The time required to return the refrigerating machine oil is shortened, and the refrigerating machine oil can be efficiently returned to the first compressor 40. Similarly, since the second on-off valve 28 is opened in a state where the refrigerating machine oil dispersed in the refrigerant circuit RC is recovered in the second gas-liquid separator 21, the second gas-liquid separator 21 refrigerates to the second compressor 50. The time required to return the machine oil is shortened, and the refrigerating machine oil can be efficiently returned to the second compressor 50.

[Second Embodiment]
The second embodiment is the same as the first embodiment except for the configurations around the first compressor and the second compressor, and FIG. 3 is incorporated. In the second embodiment, the same configurations as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the air conditioning operation control of the second embodiment is the same as that of the first embodiment, and FIG. 4 is incorporated.

(overall structure)
FIG. 4 is a configuration diagram of the air conditioner 101 according to the second embodiment.

Referring to FIG. 4, the first compression mechanism portion 141 of the first compressor 140 according to the present embodiment includes an upper cylinder 141b and a lower cylinder 141g arranged below the upper cylinder 141b. In other words, the first compressor 140 according to the present embodiment is a compressor having a two-cylinder configuration.

In the present embodiment, the first suction pipe 16 that connects the first compressor 140 and the first gas-liquid separator 11 is connected to 141 g of the lower cylinder of the first compressor 140.

The first pipe 17 of the present embodiment connects the upper cylinder 141b of the first compressor 140 and the first gas-liquid separator 11. Further, the first pipe 17 is provided with a first on-off valve 18 that allows or blocks the flow of liquid in the first pipe 17. The first on-off valve 18 is configured so that the opening and closing can be changed according to the control of the control unit 60 (shown in FIG. 3).

The second compressor 150 according to the present embodiment has the same configuration as the first compressor 140. Specifically, the second compression mechanism portion 151 of the second compressor 150 according to the present embodiment includes an upper cylinder 151b and a lower cylinder 151g arranged below the upper cylinder 151b. In other words, the second compressor 150 according to the present embodiment is a compressor having a two-cylinder configuration.

The second suction pipe 26 that connects the second compressor 150 and the second gas-liquid separator 21 is connected to 151 g of the lower cylinder of the second compressor 150.

The second pipe 27 of the present embodiment connects the upper cylinder 141b and the first gas-liquid separator 11. Further, the second pipe 27 is provided with a second on-off valve 28 that allows or blocks the flow of liquid in the second pipe 27. The second on-off valve 28 is configured so that the opening and closing can be changed according to the control of the control unit 60 (shown in FIG. 3).

(Detailed structure around the compressor)
Hereinafter, the detailed structure of the first compressor 140 and its surroundings will be described. Although not shown, the second outdoor unit 20 of the present embodiment has the same configuration as the first outdoor unit 10, and detailed description thereof will be omitted. Specifically, the second compressor 150 of the second outdoor unit 20, the second gas-liquid separator 21, the second suction pipe 26, the second pipe 27, and the second on-off valve 28 are the first outdoor unit 10. It has the same configuration as the first compressor 140, the first gas-liquid separator 11, the first suction pipe 16, the first pipe 17, and the first on-off valve 18.

FIG. 5 is a schematic vertical sectional view showing the periphery of the first compressor 140 of the present embodiment.

Referring to FIG. 5, the first compression mechanism portion 141 is attached to the front head 141a attached to the inner surface of the closed container 43, the upper cylinder 141b attached to the lower side of the front head 141a, and the lower side of the upper cylinder 141b. It is provided with an attached partition plate 141c. The front head 141a, the upper cylinder 141b, and the partition plate 141c form the upper cylinder chamber 141d. Further, the first compression mechanism unit 141 includes an upper piston 141f composed of a roller and a vane that swing in the upper cylinder chamber 141d.

Further, the first compression mechanism unit 141 includes a lower cylinder 141g attached to the lower side of the partition plate 141c and a rear head 141h attached to the lower side of the lower cylinder 141g. The lower cylinder chamber 141i is formed by the partition plate 141c, the lower cylinder 141g, and the rear head 141h. Further, the first compression mechanism unit 141 includes a lower piston 141j composed of a roller and a vane that swing in the lower cylinder chamber 141i.

The first compression mechanism portion 141 of the present embodiment includes an upper suction passage 144 formed in the upper cylinder 141b, a lower suction passage 145 formed in the lower cylinder 141g, and an upper suction passage formed in the partition plate 141c. A suction communication passage 146 that communicates the 144 and the lower suction passage 145 is provided. One end of the upper suction passage 144 is open to the upper cylinder chamber 141d, and the other end of the upper suction passage 144 is open to the outer surface of the upper cylinder 141b. Further, one end of the lower suction passage 145 is open to the lower cylinder chamber 141i, and the other end of the lower suction passage 145 is open to the outer surface of the lower cylinder 141g.

The first suction pipe 16 of the present embodiment is connected to 141 g of the lower cylinder of the first compression mechanism portion 141. Specifically, the first suction pipe 16 is connected to the lower suction passage 145 formed in the lower cylinder 141g. As a result, the lower cylinder chamber 141i of the first compressor 140 communicates with the upper side in the first gas-liquid separator 11 via the first suction pipe 16 and the lower suction passage 145. Further, the upper cylinder chamber 141d of the first compressor 140 passes through the first suction pipe 16, the lower suction passage 145, the suction communication passage 146, and the upper suction passage 144, and is the upper part in the first gas-liquid separator 11. It communicates with the side.

The first pipe 17 of the present embodiment connects the first compressor 140 and the first gas-liquid separator 11. One end of the first pipe 17 is open on the bottom side in the first gas-liquid separator 11. The bottom side in the first gas-liquid separator 11 is below the half position in the height direction of the first gas-liquid separator 11. In the state shown in FIG. 5, one end of the first pipe 17 is opened by the first liquid pool portion 11a formed in the first gas-liquid separator 11. The other end of the first pipe 17 of the present embodiment is connected to the upper cylinder 141b. Specifically, the other end of the first pipe 17 is connected to the upper suction passage 144 formed in the upper cylinder 141b. As a result, the upper cylinder chamber 141d communicates with the first liquid pool portion 11a in the first gas-liquid separator 11 via the first pipe 17 and the upper suction passage 144.

The first on-off valve 18 is provided in the first pipe 17. The first on-off valve 18 is configured so that opening and closing can be switched by the control of the control unit 60 (shown in FIG. 3).

Further, the opening of the first pipe 17 in the first gas-liquid separator 11 is opened below the opening of the first suction pipe 16 in the first gas-liquid separator 11 in the direction of gravity. In other words, the opening of the first suction pipe 16 in the first gas-liquid separator 11 is opened above the opening of the first pipe 17 in the first gas-liquid separator 11 in the direction of gravity.

In the second embodiment, the same effects as those in the first embodiment are obtained.

Further, according to the above embodiment, since the first pipe 17 is connected to the upper cylinder 141b, when the first on-off valve 18 is opened, the liquid containing the refrigerating machine oil is released from the first gas-liquid separator 11 to the first. Since it is returned to the first compression mechanism portion 141 of the first compressor 140 through the pipe 17, the structure of the air conditioner 101 can be simplified.

Similarly, according to the above embodiment, since the second pipe 27 is connected to the upper cylinder 151b, when the second on-off valve 28 is opened, the liquid containing the refrigerating machine oil is released from the second gas-liquid separator 21. Since it is returned to the second compression mechanism portion 151 of the second compressor 150 through the two pipes 27, the structure of the air conditioner 101 can be simplified.

[Third Embodiment]
The third embodiment is the same as the second embodiment except for the configurations of the first suction pipe, the second suction pipe, the first pipe, and the second pipe, and FIG. 3 is incorporated. In the third embodiment, the same configurations as those in the second embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the air conditioning operation control of the third embodiment is the same as that of the first embodiment, and FIG. 4 is incorporated.

FIG. 6 is a configuration diagram of the air conditioner 201 according to the third embodiment.

Referring to FIG. 6, the first suction pipe 216 of the present embodiment includes the upper suction pipe 216a connecting the upper cylinder 141b of the first compressor 240 and the first gas-liquid separator 11 and the first compressor 240. A lower suction pipe 216b for connecting the lower cylinder 141g and the first gas-liquid separator 11 is provided.

Further, the first pipe 17 of the present embodiment connects the upper suction pipe 216a of the first suction pipe 216 and the first gas-liquid separator 11. Further, the first pipe 17 is provided with a first on-off valve 18 that allows or blocks the flow of liquid in the first pipe 17. The first on-off valve 18 is configured so that the opening and closing can be changed according to the control of the control unit 60 (shown in FIG. 3).

The second suction pipe 226 of the present embodiment includes an upper suction pipe 226a that connects the upper cylinder 151b of the second compressor 250 and the second gas-liquid separator 21, and a lower cylinder 151g of the second compressor 250. 2 A lower suction pipe 226b for connecting the gas-liquid separator 21 is provided.

The second pipe 27 of the present embodiment connects the upper suction pipe 226a of the second suction pipe 226 and the second gas-liquid separator 21. Further, the second pipe 27 is provided with a second on-off valve 28 that allows or blocks the flow of liquid in the second pipe 27. The second on-off valve 28 is configured so that the opening and closing can be changed according to the control of the control unit 60 (shown in FIG. 3).

(Detailed structure around the compressor)
Hereinafter, the detailed structure of the first compressor 140 and its surroundings will be described. The first compressor 240 of the present embodiment has the same configuration as the first compressor 140 of the second embodiment except that it does not have a suction communication passage that communicates the upper suction passage 144 and the lower suction passage 145. The detailed description thereof will be omitted. Although not shown, the second outdoor unit 20 of the present embodiment has the same configuration as the first outdoor unit 10, and detailed description thereof will be omitted. Specifically, the second compressor 250 of the second outdoor unit 20, the second gas-liquid separator 21, the second suction pipe 226, the second pipe 27, and the second on-off valve 28 are the first outdoor unit 10. It has the same configuration as the first compressor 40, the first gas-liquid separator 11, the first suction pipe 216, the first pipe 17, and the first on-off valve 18.

FIG. 7 is a schematic vertical sectional view showing the periphery of the first compressor 240 of the present embodiment.

The upper suction pipe 216a connects the first compressor 240 and the first gas-liquid separator 11. One end of the upper suction pipe 216a is open on the upper side in the first gas-liquid separator 11. On the other hand, the other end of the upper suction pipe 216a is connected to the upper cylinder 141b of the first compression mechanism portion 141. Specifically, the other end of the upper suction pipe 216a is connected to the upper suction passage 144 formed in the upper cylinder 141b of the first compression mechanism portion 141. As a result, the upper cylinder chamber 141d of the first compressor 140 communicates with the upper side in the first gas-liquid separator 11 via the upper suction pipe 216a and the upper suction passage 144.

Further, the upper suction pipe 216a extends in the vertical direction in the first gas-liquid separator 11 and has an oil return hole 216c opened below in the first gas-liquid separator 11. In the state shown in FIG. 7, the oil return hole 216c is open to the first liquid pool portion 11a formed in the first gas-liquid separator 11. As a result, the liquid containing the refrigerating machine oil accumulated in the bottom of the first gas-liquid separator 11 is returned from the oil return hole 216c to the upper cylinder chamber 141d of the first compressor 240 via the upper suction pipe 216a. The oil return hole 216c is a hole having a small diameter so that a large amount of liquid refrigerant does not return to the first compression mechanism unit 141 during the operation of the first compressor 240.

The lower suction pipe 216b connects the first compressor 240 and the first gas-liquid separator 11. One end of the lower suction pipe 216b is open on the upper side in the first gas-liquid separator 11. On the other hand, the other end of the lower suction pipe 216b is connected to the lower cylinder 141g of the first compression mechanism portion 141. Specifically, the other end of the lower suction pipe 216b is connected to the lower suction passage 145 formed in the lower cylinder 141g of the first compression mechanism portion 141. As a result, the lower cylinder chamber 141i of the first compressor 140 communicates with the upper side in the first gas-liquid separator 11 via the lower suction pipe 216b and the lower suction passage 145.

Further, the lower suction pipe 216b extends in the vertical direction in the first gas-liquid separator 11 and has an oil return hole 216d opened below in the first gas-liquid separator 11. In the state shown in FIG. 7, the oil return hole 216d is open to the first liquid pool portion 11a formed in the first gas-liquid separator 11. As a result, the liquid containing the refrigerating machine oil accumulated in the bottom of the first gas-liquid separator 11 is returned from the oil return hole 216d to the lower cylinder chamber 141i of the first compressor 140 via the lower suction pipe 216b. .. The oil return hole 216d is a hole having a small diameter so that a large amount of liquid refrigerant does not return to the first compression mechanism unit 141 during the operation of the first compressor 140.

The first pipe 17 of the present embodiment connects the first compressor 140 and the first gas-liquid separator 11. One end of the first pipe 17 is open on the bottom side in the first gas-liquid separator 11. The bottom side in the first gas-liquid separator 11 is below the half position in the height direction of the first gas-liquid separator 11. In the state shown in FIG. 7, one end of the first pipe 17 is opened by the first liquid pool portion 11a formed in the first gas-liquid separator 11. On the other hand, the other end of the first pipe 17 of the present embodiment is connected to the upper suction pipe 216a. As a result, the first pipe 17 communicates the upper suction pipe 216a with the first liquid pool portion 11a in the first gas-liquid separator 11.

The first on-off valve 18 is provided in the first pipe 17. The first on-off valve 18 is configured so that opening and closing can be switched by the control of the control unit 60 (shown in FIG. 3).

Further, the opening of the first pipe 17 in the first gas-liquid separator 11 is in the direction of gravity more than the opening of the upper suction pipe 216a and the opening of the lower suction pipe 216b in the first gas-liquid separator 11. It is open at the bottom. In other words, the opening of the upper suction pipe 216a and the opening of the lower suction pipe 216b in the first gas-liquid separator 11 are in the direction of gravity more than the opening of the first pipe 17 in the first gas-liquid separator 11. It is open at the top.

In the third embodiment, the same effects as those in the second embodiment are obtained.

According to the above embodiment, since the first pipe 17 is connected to the upper suction pipe 216a connected to the upper cylinder 141b, when the first on-off valve 18 is opened, the liquid containing the refrigerating machine oil is released into the first air. Since the liquid separator 11 is returned to the first compression mechanism portion 141 of the first compressor 140 through the upper suction pipe 216a, the structure of the air conditioner 201 can be simplified.

Similarly, according to the above embodiment, since the second pipe 27 is connected to the upper suction pipe 226a connected to the upper cylinder 151b, when the second on-off valve 28 is opened, the liquid containing the refrigerating machine oil is released. Since it is returned from the second gas-liquid separator 21 to the second compression mechanism portion 151 of the second compressor 150 through the upper suction pipe 226a, the structure of the air conditioner 201 can be simplified.

Although the embodiments have been described above, it will be understood that various modifications of the embodiments and details are possible without departing from the purpose and scope of the claims.

For example, in the first to third embodiments, the first compressor and the second compressor have the same configuration, but the first compressor and the second compressor are not limited to this. It may have different configurations. For example, the first compressor and the second compressor may be either the one-cylinder rotary compressor shown in the first to third embodiments or the two-cylinder compressor. ..

For example, the oil return operation start condition may be a condition relating to the total operation time from the end of the previous oil return operation. Further, the oil return operation start condition may be a condition relating to the total discharge amount of the refrigerant after the air conditioning operation is started.

The oil return operation may be performed in a heating cycle.

In the first to third embodiments, the air conditioner includes two outdoor units and two indoor units, but the present invention is not limited to this, and the air conditioner may include three or more outdoor units. Often, three or more indoor units may be provided.

In the first to third embodiments, the first compressor and the second compressor are rotary compressors, but the present invention is not limited to this, and the roller and vane are integrally formed as a swing compressor. You may.

1 ... Air conditioner (refrigerator)
2A, 2B ... Closing valve 3A, 3B ... Closing valve 10 ... 1st outdoor unit 11 ... 1st gas-liquid separator 11a ... 1st liquid reservoir 12 ... 1st outdoor heat exchanger (heat source side heat exchanger)
13 ... 1st outdoor fan (heat source side fan)
14 ... First outdoor expansion valve (expansion mechanism)
15 ... 1st 4-way switching valve 16 ... 1st suction pipe 16a ... Oil return hole 17 ... 1st pipe 18 ... 1st on-off valve 20 ... 2nd outdoor unit 21 ... 2nd gas-liquid separator 21a ... 2nd liquid pool Part 22 ... Second outdoor heat exchanger (heat source side heat exchanger)
23 ... 2nd outdoor fan (heat source side fan)
24 ... Second outdoor expansion valve (expansion mechanism)
25 ... 2nd four-way switching valve 26 ... 2nd suction pipe 27 ... 2nd pipe 28 ... 2nd on-off valve 30A ... 1st indoor unit 31A ... 1st indoor heat exchanger (utility side heat exchanger)
32A ... 1st room fan (user side fan)
33A ... 1st room expansion valve 30B ... 2nd room unit 31B ... 2nd room heat exchanger (utility side heat exchanger)
32B ... 2nd room fan (user side fan)
33B ... 2nd chamber expansion valve 40 ... 1st compressor 41 ... 1st compression mechanism 41a ... Front head 41b ... Cylinder 41c ... Rear head 41d ... Cylinder chamber 41f ... Piston 42 ... 1st motor 42a ... Stator 42b ... Rotor 42c ... Shaft 43 ... Sealed container 43a ... Discharge pipe 44 ... Suction passage 50 ... Second compressor 51 ... Second compression mechanism 52 ... Second motor 60 ... Control unit 101 ... Air conditioner (refrigerator)
140 ... First compressor 141 ... First compression mechanism 141a ... Front head 141b ... Upper cylinder 141c ... Partition plate 141d ... Upper cylinder chamber 141f ... Upper piston 141g ... Lower cylinder 141h ... Rear head 141i ... Lower cylinder chamber 141j ... Lower piston 144 ... Upper suction passage 145 ... Lower suction passage 146 ... Suction communication passage 150 ... Second compressor 151b ... Upper cylinder 151g ... Lower cylinder 201 ... Air conditioner (refrigerator)
216 ... First suction pipe 216a ... Upper suction pipe 216b ... Lower suction pipe 216c ... Oil return hole 216d ... Oil return hole 226 ... Second suction pipe L1, L2 ... Communication pipe

Claims (6)

A first compressor (40, 140, 240) having a first compression mechanism (41, 141) and
A second compressor (50, 150, 250) having a second compression mechanism (51, 151), and
A first gas-liquid separation provided on the suction side of the first compressor (40, 140, 240) to separate a refrigerant containing refrigerating machine oil into a gas containing a gas refrigerant and a liquid refrigerant and a liquid containing refrigerating machine oil. Vessel (11) and
A second gas-liquid separation provided on the suction side of the second compressor (50, 150, 250) to separate the refrigerant containing the refrigerating machine oil into a gas containing a gas refrigerant and a liquid refrigerant and a liquid containing the refrigerating machine oil. Vessel (21) and
The first suction in which one end is opened on the upper side in the first gas-liquid separator (11) and the first compressor (40, 140, 240) and the first gas-liquid separator (11) are connected. Piping (16,216) and
A second suction in which one end is opened on the upper side of the second gas-liquid separator (21) and the second compressor (50, 150, 250) and the second gas-liquid separator (21) are connected. Piping (26,226) and
One end is opened on the bottom side in the first gas-liquid separator (11), and a first for connecting the first compressor (40, 140, 240) and the first gas-liquid separator (11). 1 pipe (17) and
A second for connecting the second compressor (50, 150, 250) and the second gas-liquid separator (21) by opening one end on the bottom side in the second gas-liquid separator (21). 2 piping (27) and
The first on-off valve (18) provided in the first pipe (17) and
A refrigerating apparatus (1,101,201) including a second on-off valve (28) provided in the second pipe (27). In the refrigerating apparatus (1,101,201) according to claim 1,
A refrigerating apparatus (1,101,201), characterized in that an oil leveling pipe is not provided between the first compressor (40, 140, 240) and the second compressor (50, 150, 250). In the refrigerating apparatus (1,101,201) according to claim 1 or 2.
The first compression mechanism (41, 141) of the first compressor (40, 140, 240) and the first gas-liquid separator (11) are connected by the first pipe (17).
The second compression mechanism (51, 151) of the second compressor (50, 150, 250) and the second gas-liquid separator (21) are connected by the second pipe (27). A freezing device (1,101,201). In the refrigerating apparatus (1,101,201) according to any one of claims 1 to 3, the refrigerating apparatus (1,101,201).
The first compression mechanism unit (141) is
With the lower cylinder (141 g),
It is provided with an upper cylinder (141b) arranged above the lower cylinder (141g).
The second compression mechanism unit (151)
With the lower cylinder (151g),
It is provided with an upper cylinder (151b) arranged above the lower cylinder (151g).
The first pipe (17) is connected to the upper cylinder (141b) of the first compression mechanism (141).
The first suction pipe (16) is connected to the lower cylinder (141 g) of the first compression mechanism unit (141).
The second pipe (27) is connected to the upper cylinder (151b) of the second compression mechanism (151).
The refrigerating apparatus (101) is characterized in that the second suction pipe (26) is connected to the lower cylinder (151 g) of the second compression mechanism unit (151). In the refrigerating apparatus (1,101,201) according to any one of claims 1 to 3, the refrigerating apparatus (1,101,201).
The first compression mechanism unit (141) is
With the lower cylinder (141 g),
It is provided with an upper cylinder (141b) arranged above the lower cylinder (141g).
The second compression mechanism unit (151)
With the lower cylinder (151g),
It is provided with an upper cylinder (151b) arranged above the lower cylinder (151g).
The first suction pipe (216) is
The lower suction pipe (216b) connecting the first gas-liquid separator (11) and the lower cylinder (141 g) of the first compression mechanism (141), and the lower suction pipe (216b).
It has an upper suction pipe (216a) that connects the first gas-liquid separator (11) and the upper cylinder (141b) of the first compression mechanism (141).
The second suction pipe (226) is
The lower suction pipe (226b) connecting the second gas-liquid separator (21) and the lower cylinder (151 g) of the second compression mechanism (151), and the lower suction pipe (226b).
It has an upper suction pipe (226a) for connecting the second gas-liquid separator (21) and the upper cylinder (151b) of the second compression mechanism (151).
The first pipe (17) is connected to the upper suction pipe (216a) of the first suction pipe (216).
The refrigerating apparatus (201) is characterized in that the second pipe (27) is connected to the upper suction pipe (226a) of the second suction pipe (226). In the refrigerating apparatus (1,101,201) according to any one of claims 1 to 5,
The first compressor (40,140,240) and the second compressor (50,150,250) are heat source side heat exchangers (12,22), expansion mechanisms (14,24), and utilization side heat. Included in the refrigerant circuit (RC) along with the exchanger (31)
The heat source side fan (13, 23) that supplies air to the heat source side heat exchanger (12, 22) and
The user-side fan (32) that supplies air to the user-side heat exchanger (31) and
The refrigerant circuit (RC) so that the oil return operation for returning the refrigerating machine oil dispersed in the refrigerant circuit (RC) to the first gas-liquid separator (11) and the second gas-liquid separator (21) can be executed. ), The heat source side fan (13, 23), and the control unit (60) for controlling the user side fan (32).
After executing the oil return operation, the control unit (60) stops the first compressor (40, 140, 240) and the second compressor (50, 150, 250), and then stops the first compressor (40, 150, 250). A refrigerating apparatus (1,101,201), characterized in that the on-off valve (18) and the second on-off valve (28) are opened.

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